JP2713518B2 - Manufacturing method of inorganic building board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an inorganic building board used as a base material for an inner wall or the like, and in particular, has a performance equal to or higher than that of a gypsum board, is lighter than a gypsum board and has a reduced strength due to water absorption. The present invention relates to a method for producing an inorganic building board having a low content.

[0002]

2. Description of the Related Art In general,
The base material is required to have nail holding power, bending strength, impact strength, fire resistance, water / moisture resistance, cutability and the like which are equal to or more than a certain value. For this reason, a gypsum board has been conventionally used, but the gypsum board has a specific gravity of 0.74 or more and requires a certain thickness in order to secure a desired bending strength. As a result, using a large gypsum board is too heavy and inconvenient for transportation and construction. Further, the gypsum board has a drawback that the strength of the gypsum board is remarkably reduced when water is absorbed and the strength and water resistance are extremely reduced when the paper on the back and face is separated.

[0003] For this reason, in order to solve the above-mentioned problem, for example, Japanese Patent Application Laid-Open No. 56-41880 or Japanese Patent Application Laid-Open
No. 4,188,881 discloses a lightweight high-strength inorganic plate and a method for producing the same, and has improved bending strength, water absorption, and the like.

However, even with the above-mentioned method, there is a problem that the inorganic building board is still heavy and is inconvenient for transportation and construction.

[0005] In view of the above problems, an object of the present invention is to provide a method for producing an inorganic building board which has performance equal to or higher than that of a gypsum board, is lighter than a gypsum board, and has less decrease in strength due to water absorption. And

[0006]

In order to achieve the above object, a method for producing an inorganic building board according to the present invention comprises the steps of producing a slurry containing mineral fibers, inorganic powder and a binder as essential components in a fourdrinier papermaking process. Step of obtaining wet inorganic plates to be upper and lower layers by papermaking with a machine, and forming a middle layer by forming a slurry containing mineral fibers, inorganic foam and binder as essential components with a circular net type papermaking machine A step of obtaining a wet inorganic plate, a step of arranging a wet inorganic plate as an intermediate layer between the upper and lower wet inorganic plates to obtain a laminate, a step of pressing and integrating the laminate, Heating and drying the tightly integrated laminate.

The mineral fibers forming the upper layer and the lower layer include, for example, rock wool, slag wool, mineral wool, glass fiber, carbon fiber and the like. These may be used alone or in combination of two or more. Can be used in combination. The composition ratio of the mineral fibers in the upper layer and the lower layer is preferably 20 to 45% by weight. When the content is 20% by weight or less, the inorganic powdery material described later cannot be held, and the bending strength is low.
If the amount is more than the above, the amount of the inorganic powder added becomes relatively small, so that desired surface hardness and overall hardness cannot be obtained.

The inorganic powder forming the upper layer and the lower layer is used to increase the hardness and the screwing performance while maintaining the fire resistance. For example, calcium carbonate, silica sand, micro silica, hydroxide Aluminum and the like can be given. The composition ratio of the inorganic powder in the upper layer portion and the lower layer portion is preferably set to 40 to 70% by weight. If the content is less than 40% by weight, the desired surface hardness cannot be obtained. If the content is more than 70% by weight, the drainage property is reduced, and the papermaking becomes difficult. In addition, when the inorganic powder has a particle size of about 150 μm, the strength of the lower layer portion is the largest, but the average particle diameter may be 40 μm to 300 μm.

The binder forming the upper layer and the lower layer is
It is for linking and integrating the mineral fiber and the inorganic powdery material, for example, melamine resin, synthetic resin such as phenolic resin, starch, and the like.
Alternatively, two or more kinds can be used in combination.

Further, in addition to the binder, organic fibers such as pulp and synthetic fibers, a sizing agent, a fixing agent, a flocculant, and the like are added to the slurry for forming the upper layer portion and the lower layer portion, if necessary. .

In general, the more organic fibers, the better the bending strength. Therefore, mixing organic fibers such as pulp instead of part of the inorganic fibers is effective in terms of strength and cost. It is also effective in terms of surface. However, in order to obtain an inorganic building board that can be used as a quasi-noncombustible material, it is necessary that the total amount of organic components such as a binder and pulp in the lower layer portion is 15% by weight or less. Further, in order to obtain an inorganic building board that can be used as a non-combustible material, the total amount of organic components must be reduced to 7% by weight or less. Mineral fibers need to be added.

The slurry for forming the wet inorganic plate serving as the upper layer portion and the lower layer portion contains the mineral fiber, the inorganic powder,
A binder or the like is put into water, stirred and uniformly dispersed, and the slurry is used to form wet inorganic plates as upper and lower layers using a paper machine.

As the papermaking method, a long net papermaking method capable of high-speed papermaking is used.

The upper layer and the lower layer may be formed by a wet inorganic plate obtained by the same papermaking method using a slurry of the same composition mixed with the same mineral fiber, inorganic powder, binder and the like. However, if necessary, slurries having different composition ratios in which different mineral fibers or the like are mixed may be formed on wet inorganic plates obtained by different papermaking methods, and the thickness dimensions do not need to be the same.

The mineral fibers forming the middle layer can be arbitrarily selected from the mineral fibers forming the upper layer and the lower layer. The mineral fibers can be used alone or in combination of two or more. However, it may be different from the mineral fiber constituting the lower layer. The composition ratio of the mineral fibers in the middle layer is preferably 20 to 55% by weight. When the content is 20% by weight or less, the form of the plate-like mat cannot be maintained, and when the content is 55% by weight or more, the absolute amount of the inorganic foam decreases, and the compressive strength is insufficient, so that sufficient weight reduction cannot be achieved. It is.

The inorganic foam forming the middle layer is intended to reduce the weight while maintaining the compressive strength, and includes, for example, pearlite, shirasu foam, silica flower, glass foam and the like. Alternatively, two or more kinds can be used in combination. The composition ratio of the inorganic foam in the middle layer is preferably set to 40 to 65% by weight. 4
When the content is 0% by weight or less, the strength is improved because the ratio of the mineral fibers is relatively increased, but the effect of lowering the specific gravity is not obtained. This is because the composition ratio becomes relatively small, and it becomes difficult to obtain a plate-like body by papermaking.

The binder forming the middle layer is for linking and integrating the mineral fiber and the inorganic foam, and examples thereof include synthetic resins such as melamine resin and phenol resin, and starch. These can be used alone or in combination of two or more.

[0018] In addition to the binder, organic fibers such as pulp and synthetic fibers, a sizing agent, a fixing agent, and a flocculant may be added to the slurry for forming the middle layer portion, if necessary.

Further, in order to obtain an inorganic building board which can be used as a quasi-noncombustible material, the total amount of organic components such as synthetic resin and pulp needs to be 15% by weight or less. For this reason, it is necessary to take care that the total amount of the organic components such as the binder and the pulp is within the above-mentioned range. Furthermore, in order to obtain an inorganic building board that can be used as a non-combustible material, it is necessary to make the total amount of organic components 7% by weight or less, as in the case of the upper and lower layers. For this reason, it is necessary to add a larger amount of mineral fiber than the quasi-noncombustible material.

The slurry for forming the wet inorganic plate as the middle layer is obtained by charging the above mineral fiber, inorganic foam, binder and the like into water, stirring and uniformly dispersing the same, and A wet inorganic plate to be a middle layer is formed by a papermaking machine.

As the papermaking method, a circular mesh papermaking method is used, in which the fibers are well entangled and a high strength wet inorganic plate is obtained.

Then, the above-mentioned middle layer wet inorganic plate is laminated on the lower layer portion wet inorganic plate obtained in the above step, and
By laminating the upper layer wet inorganic plate on the upper surface,
A laminate is obtained. Further, the wet inorganic plates for the upper and lower layers may be simultaneously laminated on both surfaces of the wet inorganic plate for the middle layer.

The step of pressing and integrating the laminated body is a step of extruding air between the boundary surfaces and bringing them into close contact with each other. The mineral fiber and the inorganic foam of the wet inorganic plate bite each other by the pressing, and the lower layer portion is formed. The integration of the middle and upper layers is promoted. In addition, if heating is performed at the time of pressing, the binder can be activated, which is effective in shortening the time of the subsequent drying step.

According to the present invention, since the wet inorganic plates are superposed and laminated, they are compatible with each other in joining and integrating, and at the time of pressing and / or drying, through the wet inorganic plates of the upper and lower layers. Since the supplied heat activates the binder in the middle layer, there is an advantage that interfacial separation hardly occurs and impact resistance is good.

[0025]

EXAMPLES Example 1 25 parts by weight of rock wool, 60 parts by weight of calcium carbonate,
Mixture of powdered phenol and starch 8 as binder
Parts by weight, 7 parts by weight of pulp, and a small amount of a sizing agent, a flocculant and the like were put into fresh water and stirred to obtain an aqueous slurry having a concentration of 2%. The aqueous slurry was introduced into the fourdrinier paper machines 1 and 5 shown in FIG.
Was obtained, and a 6 mm thick wet inorganic plate 6 serving as an upper layer portion was obtained.

Rock wool 40 parts by weight, Perlite 40
Parts by weight, 8 parts by weight of a mixture of powdered phenol and starch as a binder, 7 parts by weight of pulp, and a small amount of a sizing agent, a flocculant, and the like were put into clear water and stirred to obtain an aqueous slurry having a concentration of 2%. This aqueous slurry was introduced into a circular net-type paper making machine 3 shown in FIG. 1 to form a paper, thereby obtaining a 17 mm-thick wet inorganic plate 4 as an intermediate layer.

Next, on the upper surface of the 3 mm-thick wet inorganic plate 2 obtained by the fourdrinier type paper making machine 1, the 17 mm thick wet inorganic plate for the middle layer obtained by the circular net type paper making machine 3 was placed. The plate 4 is laminated, and a 6 mm-thick wet inorganic plate 6 obtained by a fourdrinier machine 5
Were laminated to obtain a laminate 7 having a total thickness of 26 mm.

The laminate 7 is pressed by a continuous belt press 8 (pressurizing force 5 kg / cm ² , heating temperature 180 ° C.) shown in FIG. 1 to obtain a laminate 7 having a thickness of 9 mm. It is cut to an appropriate length and dried with a drier 10 at a heating temperature of 180 ° C. for 60 minutes. The thickness of the lower part 11 is 1 mm, specific gravity 0.7, the thickness of the middle part 12 is 6 mm, the specific gravity 0.3, the upper part 1
3, an inorganic building board 14 having a thickness of 2 mm, a specific gravity of 0.7 and an overall thickness of 9 mm and an overall specific gravity of 0.43 was obtained and used as a sample.

(Example 2) 35 parts by weight of rock wool, 58 parts by weight of calcium carbonate,
Mixture of powdered phenol and starch 7 as binder
Example 1 A part by weight and a small amount of a sizing agent, a flocculant and the like were put into clear water and stirred to obtain an aqueous slurry having a concentration of 2%.
In the same manner as in the above, the slurry was paper-formed with a fourdrinier paper machine to obtain a wet inorganic plate having a thickness of 5 mm serving as an upper layer portion and a lower layer portion.

50 parts by weight of rock wool, perlite 44
Parts by weight, 6 parts by weight of a mixture of powdered phenol and starch as a binder, and a small amount of a sizing agent, a flocculant, and the like are put into clear water and stirred to obtain an aqueous slurry having a concentration of 2%.
This was used as a middle layer part to form a wet inorganic plate having a thickness of 23 mm as a middle layer by a circular net type paper making machine.

Next, the 23 mm thick wet inorganic plate for the middle layer is laminated on the 5 mm thick wet inorganic plate for the lower layer, and the 5 mm thick wet inorganic plate for the upper layer is disposed on the upper surface thereof. Thus, a laminate having a total thickness of 33 mm was obtained.

The laminate was pressed with a continuous belt press (pressing force: 5 kg / cm ² , heating temperature: 180 ° C.) to obtain a laminate having a thickness of 12 mm, which was cut into an appropriate length by a cutter. , Dried at 180 ° C for 90 minutes with a dryer,
The thickness of the upper and lower layers is 1.7mm, the specific gravity is 0.7, and the thickness of the middle layer is 8.
An inorganic building board having a thickness of 6 mm, a specific gravity of 0.27, an overall thickness of 12 mm, and an overall specific gravity of 0.4 was obtained and used as a sample.

Comparative Examples 1 and 2 Commercially available gypsum boards having the same outer dimensions as those of Examples 1 and 2 were used as samples.

Test Examples The results of performance tests performed on the samples of the inorganic building boards obtained in Examples 1 and 2 and commercially available gypsum board are shown below. Example 1 Comparative Example 1 Example 2 Comparative Example 2 Dimensions (mm) 910 × 1820 910 × 1820 910 × 1820 910 × 1820 Thickness (mm) 9 9 12 12 Specific gravity 0.43 0.74 0.40 0.74 Weight per sheet ( kg) 6.4 11.0 7.9 14.7 bending strength of ^{(kgf / cm 2) 60 50} 50 40 flexural strength after water absorption ^{(kgf / cm 2) 15 6} 13 5 front surface hardness (kgf) 170 220 160 220 bi scan penetrations Force (kgf) 16 27 17 35 Impact resistance (kgf · cm / cm ² ) 8 6 6 5 Fire protection Semi-combustible pass Semi-combustible pass Non-combustible pass Non-combustible pass

The test results were obtained based on the following method. Flexural strength: based on JIS 5907-1977. Flexural strength after water absorption: After immersion in water for 24 hours, JIS
Based on the test method according to 5907-1977. Surface strength: JIS HARDNESS TESTER
based on. Screw penetration force: Based on a test method according to JIS A5910. Impact resistance: Based on JIS K6911 test method. Fire protection: Based on JIS A1321.

As is clear from the above measurement results, the specific gravities of Examples 1 and 2 are 40% or less than those of Comparative Examples. That the specific gravity is smaller than 40% means that, for example, when the standard size gypsum board is about 11 kg, the inorganic building board according to the present invention of the same size is about 6.5 kg.
For this reason, in the case of a gypsum board, even if only about half of the loadable capacity of a truck or the like is available due to weight restrictions, the inorganic building board of the present application can load the full loadable capacity of a truck or the like. As a result, not only can logistics costs be significantly reduced, but also manual transportation and assembly work to the construction site is facilitated. Further, since the bending strengths of Examples 1 and 2 were higher than those of Comparative Examples 1 and 2 by 20% or more, it was found that they were not easily deformed and were easy to use. Furthermore, the decrease in bending strength after water absorption for 24 hours is smaller in Examples 1 and 2 than in Comparative Examples 1 and 2, respectively. For this reason, according to this embodiment, there is an advantage that an inorganic building board that can be used even in a humid portion can be obtained.
And, in terms of impact resistance, it is 20-
30% higher. In other words, when used as a base material, breakage is unlikely to occur, and longer use is possible.

In Examples 1 and 2, the surface hardness and the screw penetration force are smaller than those of Comparative Example. However, when the surface hardness is 150 (kgf), dents and the like hardly occur and there is no problem in practical use. . Further, the screw penetration force is required to be at least 2.5 times the weight of the inorganic building board. However, since the inorganic building board according to the present invention itself is lightweight, there is no practical problem in this respect.

Therefore, the inorganic building board according to the present invention has the same or better performance as a commercially available gypsum board.
And it turned out that it is about 40% or more lighter than a commercial gypsum board.

[0039]

As is clear from the above description, according to the method for manufacturing an inorganic building board according to the present invention, a lightweight middle layer is sandwiched between a hard and dense upper layer and a lower layer. An inorganic building board will be obtained. Therefore, according to the present invention, it is possible to obtain an inorganic building board having performance equal to or higher than that of a gypsum board, lighter than a gypsum board, and less in strength reduction due to water absorption. In addition, since all layers are manufactured by a wet method, the entanglement between the fibers is good, and the inorganic powdery or inorganic granular material can be retained during this period, so that the manufacturing can be performed even when the binder is reduced, and the incombustible material is easily obtained, Moreover, it has good impact resistance. Further, the upper and lower layers are preliminarily formed by a fourdrinier machine, and the middle layer is formed by a round net machine before forming a laminate. For this reason, papermaking can be performed using a slurry having a concentration suitable for each papermaking machine. As a result, the entire dewatering time is shortened, and a production method with high productivity is obtained. In particular, even if a large amount of fiber is added to a thin slurry, the fibers are uniformly dispersed.
There is an effect that a uniform inorganic building board can be obtained.

[Brief description of the drawings]

FIG. 1 is a process chart of Example 1 according to the present invention.

[Explanation of symbols]

1,5 ... Fourdrinier machine, 2, 4, 6 ... wet inorganic plate, 3 ...
Circular web paper machine, 7: laminated body, 8: continuous belt press, 9
... Cutter, 10 ... Dryer, 14 ... Inorganic building board.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-55-103392 (JP, A) JP-A-56-41880 (JP, A) JP-A-56-41881 (JP, A) 50417 (JP, A)

Claims (1)

(57) [Claims] Claims: 1. A step of forming a slurry containing mineral fibers, an inorganic powder and a binder as essential components by a fourdrinier machine to obtain a wet inorganic plate to be an upper layer portion and a lower layer portion; , A step of forming a slurry containing an inorganic foam and a binder as essential components by a circular net type paper machine to obtain a wet inorganic plate serving as a middle layer, and forming a middle layer between a wet inorganic plate serving as an upper layer and a lower layer An inorganic building, comprising: a step of arranging a wet inorganic plate to obtain a laminate; a step of pressing and integrating the laminate; and a step of heating and drying the pressed and integrated laminate. Plate manufacturing method.